Search results for "Quercus robur L."
showing 4 items of 4 documents
Mineral nutrients in leaves and bast of pedunculate oak (Quercus Robur L.) at different states of defoliation
1998
Abstract Adult oaks (age > 135a) with different grade of defoliation were investigated for their mineral nutrient contents in leaves and bast. In the leaves of the trees with a defoliation of more than 60 % lower concentrations of almost all nutrients were found. No differences were found between defoliation class 1 (defoliation ≤ 25 %) and defoliation class 2 (defoliation ≤ 45 %). In all defoliation classes the mineral nutrient contents are in the normal range except the contents of magnesium, which is in the range of deficiency in all defoliation classes. The mineral contents in bast showed high concentrations of cadmium, manganese zinc, and aluminum in dead trees, and in the case of cadm…
Phytopathogenic Bacteria Associated with Bacterioses of Common Oak (Quercus robur L.) in Ukraine
2022
Studying the biological characteristics of the causative agents of bacteriosis of the common oak (Quercus robur L.) (to highlight the links between the key factors of pathogenesis and bacterial groups) is a new and relevant area of research. This work aims to identify the species composition of phytopathogenic bacteria associated with common oak bacteriosis and to study the morphological, cultural, and biochemical properties of pathogens. To establish the general phytosanitary state of the surveyed stands, classical forest inventory and phytopathological (visual on based on typical symptoms of the disease and macroscopic) methods were used. The properties of isolated bacteria were studied u…
A portable NMR sensor to measure dynamic changes in the amount of water in living stems or fruit and its potential to measure sap flow.
2014
Nuclear magnetic resonance (NMR) and NMR imaging (magnetic resonance imaging) offer the possibility to quantitatively and non-invasively measure the presence and movement of water. Unfortunately, traditional NMR hardware is expensive, poorly suited for plants, and because of its bulk and complexity, not suitable for use in the field. But does it need to be? We here explore how novel, small-scale portable NMR devices can be used as a flow sensor to directly measure xylem sap flow in a poplar tree (Populus nigra L.), or in a dendrometer-like fashion to measure dynamic changes in the absolute water content of fruit or stems. For the latter purpose we monitored the diurnal pattern of growth, ex…
Sēņu sugu sastopamība ar akūtās ozolu kalšanas slimību (AOK) inficētā parastā ozola Quercus robur L. koksnē
2019
Ozolu akūtā kalšana (AOK) ir pirms 20-30 gadiem Lielbritānijā atklāta jauna un uztraukumu radoša ozolu slimība, kura pamazām turpina savu izplatību Eiropā. Latvijā šī slimība pirmo reizi konstatēta 2017.gadā Kurzemē, un ir uzsākti pētījumi, lai apzinātu slimības izplatību un varētu rast risinājumus tās ierobežošanai. Šobrīd AOK ir ļoti maz izpētīta un apzināta slimība. Joprojām nav skaidrs, kādā veidā ozoli inficējas ar AOK un kas ir šīs slimības vektori. Tiek uzskatīts, ka slimību izraisa baktērijas, bet ietekmē biotisko un abiotisko faktoru kopums. Iespējams, ka viens no slimības veicinātājiem ir patogēniskas sēnes, kuras var novājināt koku, vai pat novest to līdz bojāejai, tādēļ ir svarī…